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Atlante A, Valenti D. Mitochondrial Complex I and β-Amyloid Peptide Interplay in Alzheimer's Disease: A Critical Review of New and Old Little Regarded Findings. Int J Mol Sci 2023; 24:15951. [PMID: 37958934 PMCID: PMC10650435 DOI: 10.3390/ijms242115951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disorder and the main cause of dementia which is characterized by a progressive cognitive decline that severely interferes with daily activities of personal life. At a pathological level, it is characterized by the accumulation of abnormal protein structures in the brain-β-amyloid (Aβ) plaques and Tau tangles-which interfere with communication between neurons and lead to their dysfunction and death. In recent years, research on AD has highlighted the critical involvement of mitochondria-the primary energy suppliers for our cells-in the onset and progression of the disease, since mitochondrial bioenergetic deficits precede the beginning of the disease and mitochondria are very sensitive to Aβ toxicity. On the other hand, if it is true that the accumulation of Aβ in the mitochondria leads to mitochondrial malfunctions, it is otherwise proven that mitochondrial dysfunction, through the generation of reactive oxygen species, causes an increase in Aβ production, by initiating a vicious cycle: there is therefore a bidirectional relationship between Aβ aggregation and mitochondrial dysfunction. Here, we focus on the latest news-but also on neglected evidence from the past-concerning the interplay between dysfunctional mitochondrial complex I, oxidative stress, and Aβ, in order to understand how their interplay is implicated in the pathogenesis of the disease.
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Affiliation(s)
- Anna Atlante
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council (CNR), Via G. Amendola 122/O, 70126 Bari, Italy;
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Zeng Y, Cao S, Li N, Tang J, Lin G. Identification of key lipid metabolism-related genes in Alzheimer's disease. Lipids Health Dis 2023; 22:155. [PMID: 37736681 PMCID: PMC10515010 DOI: 10.1186/s12944-023-01918-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/04/2023] [Indexed: 09/23/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) represents profound degenerative conditions of the brain that cause significant deterioration in memory and cognitive function. Despite extensive research on the significant contribution of lipid metabolism to AD progression, the precise mechanisms remain incompletely understood. Hence, this study aimed to identify key differentially expressed lipid metabolism-related genes (DELMRGs) in AD progression. METHODS Comprehensive analyses were performed to determine key DELMRGs in AD compared to controls in GSE122063 dataset from Gene Expression Omnibus. Additionally, the ssGSEA algorithm was utilized for estimating immune cell levels. Subsequently, correlations between key DELMRGs and each immune cell were calculated specifically in AD samples. The key DELMRGs expression levels were validated via two external datasets. Furthermore, gene set enrichment analysis (GSEA) was utilized for deriving associated pathways of key DELMRGs. Additionally, miRNA-TF regulatory networks of the key DELMRGs were constructed using the miRDB, NetworkAnalyst 3.0, and Cytoscape software. Finally, based on key DELMRGs, AD samples were further segmented into two subclusters via consensus clustering, and immune cell patterns and pathway differences between the two subclusters were examined. RESULTS Seventy up-regulated and 100 down-regulated DELMRGs were identified. Subsequently, three key DELMRGs (DLD, PLPP2, and PLAAT4) were determined utilizing three algorithms [(i) LASSO, (ii) SVM-RFE, and (iii) random forest]. Specifically, PLPP2 and PLAAT4 were up-regulated, while DLD exhibited downregulation in AD cerebral cortex tissue. This was validated in two separate external datasets (GSE132903 and GSE33000). The AD group exhibited significantly altered immune cell composition compared to controls. In addition, GSEA identified various pathways commonly associated with three key DELMRGs. Moreover, the regulatory network of miRNA-TF for key DELMRGs was established. Finally, significant differences in immune cell levels and several pathways were identified between the two subclusters. CONCLUSION This study identified DLD, PLPP2, and PLAAT4 as key DELMRGs in AD progression, providing novel insights for AD prevention/treatment.
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Affiliation(s)
- Youjie Zeng
- Department of Anesthesiology, Third Xiangya Hospital, Central South University, Changsha, 410013, Hunan, China
| | - Si Cao
- Department of Anesthesiology, Third Xiangya Hospital, Central South University, Changsha, 410013, Hunan, China
| | - Nannan Li
- Department of Nephrology, Third Xiangya Hospital, Central South University, Changsha, 410013, Hunan, China
| | - Juan Tang
- Department of Nephrology, Third Xiangya Hospital, Central South University, Changsha, 410013, Hunan, China.
| | - Guoxin Lin
- Department of Anesthesiology, Third Xiangya Hospital, Central South University, Changsha, 410013, Hunan, China.
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Vrettou S, Wirth B. S-Glutathionylation and S-Nitrosylation in Mitochondria: Focus on Homeostasis and Neurodegenerative Diseases. Int J Mol Sci 2022; 23:ijms232415849. [PMID: 36555492 PMCID: PMC9779533 DOI: 10.3390/ijms232415849] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/24/2022] [Accepted: 12/12/2022] [Indexed: 12/15/2022] Open
Abstract
Redox post-translational modifications are derived from fluctuations in the redox potential and modulate protein function, localization, activity and structure. Amongst the oxidative reversible modifications, the S-glutathionylation of proteins was the first to be characterized as a post-translational modification, which primarily protects proteins from irreversible oxidation. However, a growing body of evidence suggests that S-glutathionylation plays a key role in core cell processes, particularly in mitochondria, which are the main source of reactive oxygen species. S-nitrosylation, another post-translational modification, was identified >150 years ago, but it was re-introduced as a prototype cell-signaling mechanism only recently, one that tightly regulates core processes within the cell’s sub-compartments, especially in mitochondria. S-glutathionylation and S-nitrosylation are modulated by fluctuations in reactive oxygen and nitrogen species and, in turn, orchestrate mitochondrial bioenergetics machinery, morphology, nutrients metabolism and apoptosis. In many neurodegenerative disorders, mitochondria dysfunction and oxidative/nitrosative stresses trigger or exacerbate their pathologies. Despite the substantial amount of research for most of these disorders, there are no successful treatments, while antioxidant supplementation failed in the majority of clinical trials. Herein, we discuss how S-glutathionylation and S-nitrosylation interfere in mitochondrial homeostasis and how the deregulation of these modifications is associated with Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis and Friedreich’s ataxia.
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Affiliation(s)
- Sofia Vrettou
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Correspondence: (S.V.); (B.W.)
| | - Brunhilde Wirth
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Correspondence: (S.V.); (B.W.)
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Hansen GE, Gibson GE. The α-Ketoglutarate Dehydrogenase Complex as a Hub of Plasticity in Neurodegeneration and Regeneration. Int J Mol Sci 2022; 23:12403. [PMID: 36293260 PMCID: PMC9603878 DOI: 10.3390/ijms232012403] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/06/2022] [Accepted: 10/11/2022] [Indexed: 07/30/2023] Open
Abstract
Abnormal glucose metabolism is central to neurodegeneration, and considerable evidence suggests that abnormalities in key enzymes of the tricarboxylic acid (TCA) cycle underlie the metabolic deficits. Significant recent advances in the role of metabolism in cancer provide new insight that facilitates our understanding of the role of metabolism in neurodegeneration. Research indicates that the rate-limiting step of the TCA cycle, the α-ketoglutarate dehydrogenase complex (KGDHC) and its substrate alpha ketoglutarate (KG), serve as a signaling hub that regulates multiple cellular processes: (1) is the rate-limiting step of the TCA cycle, (2) is sensitive to reactive oxygen species (ROS) and produces ROS, (3) determines whether KG is used for energy or synthesis of compounds to support growth, (4) regulates the cellular responses to hypoxia, (5) controls the post-translational modification of hundreds of cell proteins in the mitochondria, cytosol, and nucleus through succinylation, (6) controls critical aspects of transcription, (7) modulates protein signaling within cells, and (8) modulates cellular calcium. The primary focus of this review is to understand how reductions in KGDHC are translated to pathologically important changes that underlie both neurodegeneration and cancer. An understanding of each role is necessary to develop new therapeutic strategies to treat neurodegenerative disease.
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Affiliation(s)
- Grace E. Hansen
- Department of Biology, University of Massachusetts, Lowell, MA 01852, USA
| | - Gary E. Gibson
- Weill Cornell Medicine, Brain and Mind Research Institute, Burke Neurological Institute, White Plains, NY 10605, USA
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Sayehmiri F, Khodagholi F, Pourbadie HG, Naderi N, Aliakbarzadeh F, Hashemi R, Naderi S, Motamedi F. Phosphonate analog of 2-oxoglutarate regulates glutamate-glutamine homeostasis and counteracts amyloid beta induced learning and memory deficits in rats. Exp Gerontol 2022; 168:111944. [PMID: 36064157 DOI: 10.1016/j.exger.2022.111944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/28/2022] [Accepted: 08/24/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND Metabolic alteration is a mainstream concept underlying the cognitive decline in neurodegenerative disorders including Alzheimer's disease (AD). Mitochondrial enzyme α-ketoglutarate dehydrogenase complex (α-KGDHC) seems to play a dual-edged sword role in cytotoxic insult. Here, using succinyl phosphonate (SP), a specific α-KGDHC inhibitor, we aimed to examine its potential action on AD progression. METHODS Male Wistar rats were assigned to two separate experiments. First, they were bilaterally microinjected into the dorsal CA1 area by amyloid-beta (Aβ)25-35 for four consecutive days. Seven days after the last injection, they were trained to acquire Morris Water Maze (MWM) task for three successive days when they were treated with SP after each training session. In the second experiment, SP was administered 30 min after the first Aβ microinjection and behavioral tests were performed one week after the last Aβ administration. The activity of glutamate dehydrogenase (GDH), and glutamine synthetase (GS), as key enzymes involved in glutamate-glutamine homeostasis and histological assays were evaluated in the hippocampi. RESULTS Our behavioral results indicated that post-training SP treatment enhanced task acquisition but did not change memory performance in Aβ-treated rats. However, administration of SP at the time of Aβ injection precludes the deteriorative effect of Aβ and neuronal injury on both spatial learning and memory performances indicating its preventive action against Aβ pathology at its early stages. Measurement of enzymes activity shows that α-KGDHC activity was reduced in the Aβ treated group, and SP administration restored its activity; also, GDH and GS activities were increased and decreased respectively due to Aβ, and SP reversed the action of Aβ on these enzymes. CONCLUSIONS This study proposes that SP possibly a promising therapeutic approach to improve memory impairment in AD, especially in the early phases of this disease.
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Affiliation(s)
- Fatemeh Sayehmiri
- School of Medicine, Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fariba Khodagholi
- Neurobilogy Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Nima Naderi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Faezeh Aliakbarzadeh
- Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Reza Hashemi
- School of Medicine, Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soudabeh Naderi
- School of Medicine, Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fereshteh Motamedi
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Aβ-induced mitochondrial dysfunction in neural progenitors controls KDM5A to influence neuronal differentiation. EXPERIMENTAL & MOLECULAR MEDICINE 2022; 54:1461-1471. [PMID: 36056186 PMCID: PMC9534996 DOI: 10.1038/s12276-022-00841-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 06/02/2022] [Accepted: 06/30/2022] [Indexed: 11/08/2022]
Abstract
Mitochondria in neural progenitors play a crucial role in adult hippocampal neurogenesis by being involved in fate decisions for differentiation. However, the molecular mechanisms by which mitochondria are related to the genetic regulation of neuronal differentiation in neural progenitors are poorly understood. Here, we show that mitochondrial dysfunction induced by amyloid-beta (Aβ) in neural progenitors inhibits neuronal differentiation but has no effect on the neural progenitor stage. In line with the phenotypes shown in Alzheimer's disease (AD) model mice, Aβ-induced mitochondrial damage in neural progenitors results in deficits in adult hippocampal neurogenesis and cognitive function. Based on hippocampal proteome changes after mitochondrial damage in neural progenitors identified through proteomic analysis, we found that lysine demethylase 5A (KDM5A) in neural progenitors epigenetically suppresses differentiation in response to mitochondrial damage. Mitochondrial damage characteristically causes KDM5A degradation in neural progenitors. Since KDM5A also binds to and activates neuronal genes involved in the early stage of differentiation, functional inhibition of KDM5A consequently inhibits adult hippocampal neurogenesis. We suggest that mitochondria in neural progenitors serve as the checkpoint for neuronal differentiation via KDM5A. Our findings not only reveal a cell-type-specific role of mitochondria but also suggest a new role of KDM5A in neural progenitors as a mediator of retrograde signaling from mitochondria to the nucleus, reflecting the mitochondrial status.
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Perspectives on the Molecular Mediators of Oxidative Stress and Antioxidant Strategies in the Context of Neuroprotection and Neurolongevity: An Extensive Review. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:7743705. [PMID: 36062188 PMCID: PMC9439934 DOI: 10.1155/2022/7743705] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 08/09/2022] [Indexed: 12/11/2022]
Abstract
Molecules with at least one unpaired electron in their outermost shell are known as free radicals. Free radical molecules are produced either within our bodies or by external sources such as ozone, cigarette smoking, X-rays, industrial chemicals, and air pollution. Disruption of normal cellular homeostasis by redox signaling may result in cardiovascular, neurodegenerative diseases and cancer. Although ROS (reactive oxygen species) are formed in the GI tract, little is known about how they contribute to pathophysiology and disease etiology. When reactive oxygen species and antioxidants are in imbalance in our bodies, they can cause cell structure damage, neurodegenerative diseases, diabetes, hypercholesterolemia, atherosclerosis, cancer, cardiovascular diseases, metabolic disorders, and other obesity-related disorders, as well as protein misfolding, mitochondrial dysfunction, glial cell activation, and subsequent cellular apoptosis. Neuron cells are gradually destroyed in neurodegenerative diseases. The production of inappropriately aggregated proteins is strongly linked to oxidative stress. This review's goal is to provide as much information as possible about the numerous neurodegenerative illnesses linked to oxidative stress. The possibilities of multimodal and neuroprotective therapy in human illness, using already accessible medications and demonstrating neuroprotective promise in animal models, are highlighted. Neuroprotection and neurolongevity may improve from the use of bioactive substances from medicinal herbs like Allium stadium, Celastrus paniculatus, and Centella asiatica. Many neuroprotective drugs' possible role has been addressed. Preventing neuroinflammation has been demonstrated in several animal models.
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Vodičková A, Koren SA, Wojtovich AP. Site-specific mitochondrial dysfunction in neurodegeneration. Mitochondrion 2022; 64:1-18. [PMID: 35182728 PMCID: PMC9035127 DOI: 10.1016/j.mito.2022.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/18/2022] [Accepted: 02/14/2022] [Indexed: 02/07/2023]
Abstract
Mitochondria are essential for neuronal survival and mitochondrial dysfunction is a hallmark of neurodegeneration. The loss in mitochondrial energy production, oxidative stress, and changes in calcium handling are associated with neurodegenerative diseases; however, different sites and types of mitochondrial dysfunction are linked to distinct neuropathologies. Understanding the causal or correlative relationship between changes in mitochondria and neuropathology will lead to new therapeutic strategies. Here, we summarize the evidence of site-specific mitochondrial dysfunction and mitochondrial-related clinical trials for neurodegenerative diseases. We further discuss potential therapeutic approaches, such as mitochondrial transplantation, restoration of mitochondrial function, and pharmacological alleviation of mitochondrial dysfunction.
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Affiliation(s)
- Anežka Vodičková
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, USA.
| | - Shon A Koren
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, USA.
| | - Andrew P Wojtovich
- Department of Anesthesiology and Perioperative Medicine, University of Rochester Medical Center, Rochester, NY, USA; Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA.
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Yao L, Xu X, Xu Y, Li C, Xie F, Guo M, Liu Z, Liu X. OGDHL ameliorates cognitive impairment and Alzheimer's disease-like pathology via activating Wnt/β-catenin signaling in Alzheimer's disease mice. Behav Brain Res 2022; 418:113673. [PMID: 34798170 DOI: 10.1016/j.bbr.2021.113673] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 11/11/2021] [Accepted: 11/13/2021] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is one of the most common neurodegenerative diseases related to several types of pathophysiological signs, including β-amyloid (Aβ) plaque accumulation, neuroinflammation, and neurofibrillary tangles. Similar to one of the three subunits of α-ketoglutarate dehydrogenase complex (KGDHC), oxoglutarate dehydrogenase-like (OGDHL) appears to be downregulated in triple-transgenic Alzheimer's (3 × Tg-AD) mice. KGDHC activity is specifically reduced in the brains of people with AD. However, the underlying mechanism of OGDHL in the cause of AD is still unknown. Herein, we confirmed the low expression of OGDHL in the brain of 3 × Tg-AD based on real-time quantitative PCR, Western blot, and immunohistochemistry. We also found that the upregulation of OGDHL can reduce the memory deficits of 3 × Tg-AD mice, thereby reminding its nervous system neuroprotective effect in AD. Next, we confirmed that the increase in OGDHL could reduce neuroinflammation, amyloid plaque load, and tau phosphorylation in 3 × Tg-AD mice. Additionally, we showed that the overexpression of OGDHL could activate Wnt/β-catenin signaling based on the expression of Wnt7B in vitro. Taken together, the results show that the rise of OGDHL reasonably improves the cognitive functions according to the activation of the Wnt/β-catenin signaling pathway. Therefore, this enzyme may be a potential strategy for AD treatment.
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Affiliation(s)
- Li Yao
- Department of Geriatric Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xuemin Xu
- Department of Geriatric Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yukun Xu
- Department of Geriatric Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Chunyan Li
- Department of Internal Medicine of Traditional Chinese Medicine, Shizhong District People's Hospital of Jinan, Jinan, China
| | - Fang Xie
- School of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Minghao Guo
- Department of Geriatric Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Zhaoyang Liu
- Department of Geriatric Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xiaoming Liu
- Department of Geriatric Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China.
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Ahmad W, Ebert PR. Suppression of a core metabolic enzyme dihydrolipoamide dehydrogenase ( dld) protects against amyloid beta toxicity in C. elegans model of Alzheimer's disease. Genes Dis 2021; 8:849-866. [PMID: 34522713 PMCID: PMC8427249 DOI: 10.1016/j.gendis.2020.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/24/2020] [Accepted: 08/14/2020] [Indexed: 01/24/2023] Open
Abstract
A decrease in energy metabolism is associated with Alzheimer's disease (AD), but it is not known whether the observed decrease exacerbates or protects against the disease. The importance of energy metabolism in AD is reinforced by the observation that variants of dihydrolipoamide dehydrogenase (DLD), is genetically linked to late-onset AD. To determine whether DLD is a suitable therapeutic target, we suppressed the dld-1 gene in Caenorhabditis elegans that express human Aβ peptide in either muscles or neurons. Suppression of the dld-1 gene resulted in significant restoration of vitality and function that had been degraded by Aβ pathology. This included protection of neurons and muscles cells. The observed decrease in proteotoxicity was associated with a decrease in the formation of toxic oligomers rather than a decrease in the abundance of the Aβ peptide. The mitochondrial uncoupler, carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), which like dld-1 gene expression inhibits ATP synthesis, had no significant effect on Aβ toxicity. Proteomics data analysis revealed that beneficial effects after dld-1 suppression could be due to change in energy metabolism and activation of the pathways associated with proteasomal degradation, improved cell signaling and longevity. Thus, some features unique to dld-1 gene suppression are responsible for the therapeutic benefit. By direct genetic intervention, we have shown that acute inhibition of dld-1 gene function may be therapeutically beneficial. This result supports the hypothesis that lowering energy metabolism protects against Aβ pathogenicity and that DLD warrants further investigation as a therapeutic target.
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Affiliation(s)
- Waqar Ahmad
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul R. Ebert
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
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Wong KY, Roy J, Fung ML, Heng BC, Zhang C, Lim LW. Relationships between Mitochondrial Dysfunction and Neurotransmission Failure in Alzheimer's Disease. Aging Dis 2020; 11:1291-1316. [PMID: 33014538 PMCID: PMC7505271 DOI: 10.14336/ad.2019.1125] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022] Open
Abstract
Besides extracellular deposition of amyloid beta and formation of phosphorylated tau in the brains of patients with Alzheimer's disease (AD), the pathogenesis of AD is also thought to involve mitochondrial dysfunctions and altered neurotransmission systems. However, none of these components can describe the diverse cognitive, behavioural, and psychiatric symptoms of AD without the pathologies interacting with one another. The purpose of this review is to understand the relationships between mitochondrial and neurotransmission dysfunctions in terms of (1) how mitochondrial alterations affect cholinergic and monoaminergic systems via disruption of energy metabolism, oxidative stress, and apoptosis; and (2) how different neurotransmission systems drive mitochondrial dysfunction via increasing amyloid beta internalisation, oxidative stress, disruption of mitochondrial permeabilisation, and mitochondrial trafficking. All these interactions are separately discussed in terms of neurotransmission systems. The association of mitochondrial dysfunctions with alterations in dopamine, norepinephrine, and histamine is the prospective goal in this research field. By unfolding the complex interactions surrounding mitochondrial dysfunction in AD, we can better develop potential treatments to delay, prevent, or cure this devastating disease.
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Affiliation(s)
- Kan Yin Wong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Jaydeep Roy
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Man Lung Fung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Boon Chin Heng
- Peking University School of Stomatology, Beijing, China.
| | - Chengfei Zhang
- Endodontology, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
| | - Lee Wei Lim
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
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The Role of Mitochondria in Inflammation: From Cancer to Neurodegenerative Disorders. J Clin Med 2020; 9:jcm9030740. [PMID: 32182899 PMCID: PMC7141240 DOI: 10.3390/jcm9030740] [Citation(s) in RCA: 116] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/24/2020] [Accepted: 03/06/2020] [Indexed: 12/14/2022] Open
Abstract
The main features that are commonly attributed to mitochondria consist of the regulation of cell proliferation, ATP generation, cell death and metabolism. However, recent scientific advances reveal that the intrinsic dynamicity of the mitochondrial compartment also plays a central role in proinflammatory signaling, identifying these organelles as a central platform for the control of innate immunity and the inflammatory response. Thus, mitochondrial dysfunctions have been related to severe chronic inflammatory disorders. Strategies aimed at reestablishing normal mitochondrial physiology could represent both preventive and therapeutic interventions for various pathologies related to exacerbated inflammation. Here, we explore the current understanding of the intricate interplay between mitochondria and the innate immune response in specific inflammatory diseases, such as neurological disorders and cancer.
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Dobolyi A, Bago A, Palkovits M, Nemeria NS, Jordan F, Doczi J, Ambrus A, Adam-Vizi V, Chinopoulos C. Exclusive neuronal detection of KGDHC-specific subunits in the adult human brain cortex despite pancellular protein lysine succinylation. Brain Struct Funct 2020; 225:639-667. [PMID: 31982949 PMCID: PMC7046601 DOI: 10.1007/s00429-020-02026-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 01/11/2020] [Indexed: 12/31/2022]
Abstract
The ketoglutarate dehydrogenase complex (KGDHC) consists of three different subunits encoded by OGDH (or OGDHL), DLST, and DLD, combined in different stoichiometries. DLD subunit is shared between KGDHC and pyruvate dehydrogenase complex, branched-chain alpha-keto acid dehydrogenase complex, and the glycine cleavage system. Despite KGDHC's implication in neurodegenerative diseases, cell-specific localization of its subunits in the adult human brain has never been investigated. Here, we show that immunoreactivity of all known isoforms of OGDHL, OGDH, and DLST was detected exclusively in neurons of surgical human cortical tissue samples identified by their morphology and visualized by double labeling with fluorescent Nissl, while being absent from glia expressing GFAP, Aldhl1, myelin basic protein, Olig2, or IBA1. In contrast, DLD immunoreactivity was evident in both neurons and glia. Specificity of anti-KGDHC subunits antisera was verified by a decrease in staining of siRNA-treated human cancer cell lines directed against the respective coding gene products; furthermore, immunoreactivity of KGDHC subunits in human fibroblasts co-localized > 99% with mitotracker orange, while western blotting of 63 post-mortem brain samples and purified recombinant proteins afforded further assurance regarding antisera monospecificity. KGDHC subunit immunoreactivity correlated with data from the Human Protein Atlas as well as RNA-Seq data from the Allen Brain Atlas corresponding to genes coding for KGDHC components. Protein lysine succinylation, however, was immunohistochemically evident in all cortical cells; this was unexpected, because this posttranslational modification requires succinyl-CoA, the product of KGDHC. In view of the fact that glia of the human brain cortex lack succinate-CoA ligase, an enzyme producing succinyl-CoA when operating in reverse, protein lysine succinylation in these cells must exclusively rely on propionate and/or ketone body metabolism or some other yet to be discovered pathway encompassing succinyl-CoA.
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Affiliation(s)
- Arpad Dobolyi
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Hungarian Academy of Sciences and Eotvos Lorand University, Budapest, 1117, Hungary
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, 1094, Hungary
| | - Attila Bago
- National Institute of Neurosurgery, Budapest, 1145, Hungary
| | - Miklos Palkovits
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Hungarian Academy of Sciences and Eotvos Lorand University, Budapest, 1117, Hungary
| | - Natalia S Nemeria
- Department of Chemistry, Rutgers University, Newark, NJ, 07102-1811, USA
| | - Frank Jordan
- Department of Chemistry, Rutgers University, Newark, NJ, 07102-1811, USA
| | - Judit Doczi
- Department of Medical Biochemistry, Semmelweis University, Tuzolto st. 37-47, Budapest, 1094, Hungary
| | - Attila Ambrus
- Department of Medical Biochemistry, Semmelweis University, Tuzolto st. 37-47, Budapest, 1094, Hungary
- MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, Semmelweis University, Tuzolto st. 37-47, Budapest, 1094, Hungary
- MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Tuzolto st. 37-47, Budapest, 1094, Hungary.
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14
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Pereira CF, Santos AE, Moreira PI, Pereira AC, Sousa FJ, Cardoso SM, Cruz MT. Is Alzheimer's disease an inflammasomopathy? Ageing Res Rev 2019; 56:100966. [PMID: 31577960 DOI: 10.1016/j.arr.2019.100966] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/28/2019] [Accepted: 09/27/2019] [Indexed: 01/04/2023]
Abstract
Alzheimer's disease (AD) is the most common form of dementia in the elderly and, despite the tremendous efforts researchers have put into AD research, there are no effective options for prevention and treatment of the disease. The best way to reach this goal is to clarify the mechanisms involved in the onset and progression of AD. In the last few years the views about the drivers of AD have been changing and nowadays it is believed that neuroinflammation takes center stage in disease pathogenesis. Herein, we provide an overview about the role of neuroinflammation in AD describing the role of microglia and astroglia is this process. Then, we will debate the NLRP3 inflammasome putting the focus on its activation through the canonical, non-canonical and alternative pathways and the triggers involved herein namely endoplasmic reticulum stress, mitochondrial dysfunction, reactive oxygen species and amyloid β peptide. Data supporting the hypothesis that inflammasome-mediated peripheral inflammation may contribute to AD pathology will be presented. Finally, a brief discussion about the therapeutic potential of NLRP3 inflammasome modulation is also provided.
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15
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Yu H, Jiang X, Lin X, Zhang Z, Wu D, Zhou L, Liu J, Yang X. Hippocampal Subcellular Organelle Proteomic Alteration of Copper-Treated Mice. Toxicol Sci 2019; 164:250-263. [PMID: 29617964 DOI: 10.1093/toxsci/kfy082] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Copper neurotoxicity has been implicated in multiple neurological diseases. However, there is a lack of deep understanding on copper neurotoxicity, especially for low-dose copper exposure. In this study, we investigated the effects of chronic, low-dose copper treatment (0.13 ppm copper chloride in drinking water) on hippocampal mitochondrial and nuclear proteome in mice by 2-dimensional fluorescence difference gel electrophoresis coupled with MALDI-TOF-MS/MS. Behavioral tests revealed that low-dose copper caused spatial memory impairment, DNA oxidative damage as well as loss of synaptic proteins. Proteomic analysis revealed modulation of 31 hippocampal mitochondrial proteins (15 increased and 16 decreased), and 46 hippocampal nuclear proteins (18 increased and 28 decreased) in copper-treated versus untreated mice. Bioinformatic analysis indicated that these differentially expressed proteins are mainly involved energy metabolism (NDUV1, COX5B, IDH3A, and PGAM1), synapses (complexin-2, synapsin-2), DNA damage (PDIA3), apoptosis (GRP75), and oxidative stress (SODC, PRDX3). Among these differentially expressed proteins, synapsin-2, a synaptic-related protein, was found to be significantly decreased as confirmed by Western-blot analysis. In addition, we found that superoxide dismutase [Cu-Zn] (SODC), a copper ion target protein, was identified to be decreased in copper-treated mice versus untreated mice. We also found that stathmin (STMN1), a microtubule-destabilizing neuroprotein, was significantly decreased in hippocampal nuclei of copper-treated mice versus untreated mice. Taken together, we conclude that low-dose copper exposure causes spatial memory impairment and perturbs multiple biological/pathogenic processes by dysregulating the mitochondrial and nuclear proteome, particularly the proteins related to respiratory chain, synaptic vesicle fusion, axonal/neurtic integrity, and oxidative stress. The change of STMN1 and SODC may represent early novel biomarkers of copper neurotoxicity.
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Affiliation(s)
- Haitao Yu
- Key Laboratory of Modern Toxicology of Shenzhen, Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Xin Jiang
- Department of Geriatrics, The Second Clinical Medical College (Shenzhen People's Hospital), Jinan University, Guangdong, China
| | - Xuemei Lin
- Key Laboratory of Modern Toxicology of Shenzhen, Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Zaijun Zhang
- Institute of New Drug Research and Guangzhou, Key Laboratory of Innovative Chemical Drug Research in Cardio-cerebrovascular Diseases, Jinan University College of Pharmacy, Guangzhou 510632, China
| | - Desheng Wu
- Key Laboratory of Modern Toxicology of Shenzhen, Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Li Zhou
- Key Laboratory of Modern Toxicology of Shenzhen, Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Jianjun Liu
- Key Laboratory of Modern Toxicology of Shenzhen, Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Xifei Yang
- Key Laboratory of Modern Toxicology of Shenzhen, Institute of Toxicology, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
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16
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Ahmad W. Dihydrolipoamide dehydrogenase suppression induces human tau phosphorylation by increasing whole body glucose levels in a C. elegans model of Alzheimer's Disease. Exp Brain Res 2018; 236:2857-2866. [PMID: 30056470 DOI: 10.1007/s00221-018-5341-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 07/21/2018] [Indexed: 12/01/2022]
Abstract
The microtubule associated tau protein becomes hyperphosphorylated in Alzheimer's disease (AD). While hyperphosphorylation promotes neurodegeneration, the cause and consequences of this abnormal modification are poorly understood. As impaired energy metabolism is an important hallmark of AD progression, we tested whether it could trigger phosphorylation of human tau protein in a transgenic Caenorhabditis elegans model of AD. We found that inhibition of a mitochondrial enzyme of energy metabolism, dihydrolipoamide dehydrogenase (DLD) results in elevated whole-body glucose levels as well as increased phosphorylation of tau. Hyperglycemia and tau phosphorylation were induced by either RNAi suppression of the dld-1 gene or by inhibition of the DLD enzyme by the inhibitor, 2-methoxyindole-2-carboxylic acid (MICA). Although the calcium ionophore A23187 could reduce tau phosphorylation induced by either chemical or genetic suppression of DLD, it was unable to reduce tau phosphorylation induced by hyperglycemia. While inhibition of the dld-1 gene or treatment with MICA partially reversed the inhibition of acetylcholine neurotransmission by tau, neither treatment affected tau inhibited mobility. Conclusively, any abnormalities in energy metabolism were found to significantly affect the AD disease pathology.
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Affiliation(s)
- Waqar Ahmad
- School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia.
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17
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Ahmad W, Ebert PR. 5-Methoxyindole-2-carboxylic acid (MICA) suppresses Aβ-mediated pathology in C. elegans. Exp Gerontol 2018; 108:215-225. [DOI: 10.1016/j.exger.2018.04.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 04/02/2018] [Accepted: 04/26/2018] [Indexed: 12/22/2022]
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18
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Abstract
Alzheimer's disease (AD) is characterized by brain deposition of amyloid plaques and tau neurofibrillary tangles along with steady cognitive decline. Synaptic damage, an early pathological event, correlates strongly with cognitive deficits and memory loss. Mitochondria are essential organelles for synaptic function. Neurons utilize specialized mechanisms to drive mitochondrial trafficking to synapses in which mitochondria buffer Ca2+ and serve as local energy sources by supplying ATP to sustain neurotransmitter release. Mitochondrial abnormalities are one of the earliest and prominent features in AD patient brains. Amyloid-β (Aβ) and tau both trigger mitochondrial alterations. Accumulating evidence suggests that mitochondrial perturbation acts as a key factor that is involved in synaptic failure and degeneration in AD. The importance of mitochondria in supporting synaptic function has made them a promising target of new therapeutic strategies for AD. Here, we review the molecular mechanisms regulating mitochondrial function at synapses, highlight recent findings on the disturbance of mitochondrial dynamics and transport in AD, and discuss how these alterations impact synaptic vesicle release and thus contribute to synaptic pathology associated with AD.
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Cardoso S, Carvalho C, Correia SC, Seiça RM, Moreira PI. Alzheimer's Disease: From Mitochondrial Perturbations to Mitochondrial Medicine. Brain Pathol 2018; 26:632-47. [PMID: 27327899 DOI: 10.1111/bpa.12402] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 05/18/2016] [Indexed: 01/17/2023] Open
Abstract
Age-related neurodegenerative diseases such as Alzheimer's disease (AD) are distressing conditions causing countless levels of suffering for which treatment is often insufficient or inexistent. Considered to be the most common cause of dementia and an incurable, progressive neurodegenerative disorder, the intricate pathogenic mechanisms of AD continue to be revealed and, consequently, an effective treatment needs to be developed. Among the diverse hypothesis that have been proposed to explain AD pathogenesis, the one concerning mitochondrial dysfunction has raised as one of the most discussed with an actual acceptance in the field. It posits that manipulating mitochondrial function and understanding the deficits that result in mitochondrial injury may help to control and/or limit the development of AD. To achieve such goal, the concept of mitochondrial medicine places itself as a promising gathering of strategies to directly manage the major insidious disturbances of mitochondrial homeostasis as well as attempts to directly or indirectly manage its consequences in the context of AD. The aim of this review is to summarize the evolution that occurred from the establishment of mitochondrial homeostasis perturbation as masterpieces in AD pathogenesis up until the development of mitochondrial medicine. Following a brief glimpse in the past and current hypothesis regarding the triad of aging, mitochondria and AD, this manuscript will address the major mechanisms currently believed to participate in above mentioned events. Both pharmacological and lifestyle interventions will also be reviewed as AD-related mitochondrial therapeutics.
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Affiliation(s)
- Susana Cardoso
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Cristina Carvalho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Sónia C Correia
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Raquel M Seiça
- Laboratory of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,IBILI-Institute for Biomedical Imaging and Life Sciences, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Paula I Moreira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Laboratory of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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20
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Ambrus A, Adam-Vizi V. Human dihydrolipoamide dehydrogenase (E3) deficiency: Novel insights into the structural basis and molecular pathomechanism. Neurochem Int 2017; 117:5-14. [PMID: 28579060 DOI: 10.1016/j.neuint.2017.05.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/22/2017] [Accepted: 05/30/2017] [Indexed: 11/18/2022]
Abstract
This review summarizes our present view on the molecular pathogenesis of human (h) E3-deficiency caused by a variety of genetic alterations with a special emphasis on the moonlighting biochemical phenomena related to the affected (dihydro)lipoamide dehydrogenase (LADH, E3, gene: dld), in particular the generation of reactive oxygen species (ROS). E3-deficiency is a rare autosomal recessive genetic disorder frequently presenting with a neonatal onset and premature death; the highest carrier rate of a single pathogenic dld mutation (1:94-1:110) was found among Ashkenazi Jews. Patients usually die during acute episodes that generally involve severe metabolic decompensation and lactic acidosis leading to neurological, cardiological, and/or hepatological manifestations. The disease owes its severity to the fact that LADH is the common E3 subunit of the alpha-ketoglutarate (KGDHc), pyruvate (PDHc), and branched-chain α-keto acid dehydrogenase complexes and is also part of the glycine cleavage system, hence the malfunctioning of LADH simultaneously incapacitates several central metabolic pathways. Nevertheless, the clinical pictures are usually not unequivocally portrayed through the loss of LADH activities and imply auxiliary mechanisms that exacerbate the symptoms and outcomes of this disorder. Enhanced ROS generation by disease-causing hE3 variants as well as by the E1-E2 subcomplex of the hKGDHc likely contributes to selected pathogeneses of E3-deficiency, which could be targeted by specific drugs or antioxidants; lipoic acid was demonstrated to be a potent inhibitor of ROS generation by hE3 in vitro. Flavin supplementation might prove to be beneficial for those mutations triggering FAD loss in the hE3 component. Selected pathogenic hE3 variants lose their affinity for the E2 component of the hPDHc, a mechanism which warrants scrutiny also for other E3-haboring complexes.
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Affiliation(s)
- Attila Ambrus
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, Hungary.
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, Hungary.
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21
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Biomedical applications of cell- and tissue-specific metabolic network models. J Biomed Inform 2017; 68:35-49. [DOI: 10.1016/j.jbi.2017.02.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 02/21/2017] [Accepted: 02/23/2017] [Indexed: 12/17/2022]
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22
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Anthocyanins protect from complex I inhibition and APPswe mutation through modulation of the mitochondrial fission/fusion pathways. Biochim Biophys Acta Mol Basis Dis 2016; 1862:2110-2118. [DOI: 10.1016/j.bbadis.2016.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/07/2016] [Accepted: 08/04/2016] [Indexed: 11/23/2022]
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23
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Ambrus A, Nemeria NS, Torocsik B, Tretter L, Nilsson M, Jordan F, Adam-Vizi V. Formation of reactive oxygen species by human and bacterial pyruvate and 2-oxoglutarate dehydrogenase multienzyme complexes reconstituted from recombinant components. Free Radic Biol Med 2015; 89:642-50. [PMID: 26456061 PMCID: PMC4684775 DOI: 10.1016/j.freeradbiomed.2015.10.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 09/18/2015] [Accepted: 10/03/2015] [Indexed: 01/25/2023]
Abstract
Individual recombinant components of pyruvate and 2-oxoglutarate dehydrogenase multienzyme complexes (PDHc, OGDHc) of human and Escherichia coli (E. coli) origin were expressed and purified from E. coli with optimized protocols. The four multienzyme complexes were each reconstituted under optimal conditions at different stoichiometric ratios. Binding stoichiometries for the highest catalytic efficiency were determined from the rate of NADH generation by the complexes at physiological pH. Since some of these complexes were shown to possess 'moonlighting' activities under pathological conditions often accompanied by acidosis, activities were also determined at pH 6.3. As reactive oxygen species (ROS) generation by the E3 component of hOGDHc is a pathologically relevant feature, superoxide generation by the complexes with optimal stoichiometry was measured by the acetylated cytochrome c reduction method in both the forward and the reverse catalytic directions. Various known affectors of physiological activity and ROS production, including Ca(2+), ADP, lipoylation status or pH, were investigated. The human complexes were also reconstituted with the most prevalent human pathological mutant of the E3 component, G194C and characterized; isolated human E3 with the G194C substitution was previously reported to have an enhanced ROS generating capacity. It is demonstrated that: i. PDHc, similarly to OGDHc, is able to generate ROS and this feature is displayed by both the E. coli and human complexes, ii. Reconstituted hPDHc generates ROS at a significantly higher rate as compared to hOGDHc in both the forward and the reverse reactions when ROS generation is calculated for unit mass of their common E3 component, iii. The E1 component or E1-E2 subcomplex generates significant amount of ROS only in hOGDHc; iv. Incorporation of the G194C variant of hE3, the result of a disease-causing mutation, into reconstituted hOGDHc and hPDHc indeed leads to a decreased activity of both complexes and higher ROS generation by only hOGDHc and only in its reverse reaction.
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Affiliation(s)
- Attila Ambrus
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Natalia S Nemeria
- Department of Chemistry, Rutgers, the State University, Newark, NJ 07102, USA
| | - Beata Torocsik
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Laszlo Tretter
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Mattias Nilsson
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary
| | - Frank Jordan
- Department of Chemistry, Rutgers, the State University, Newark, NJ 07102, USA
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest, 1094, Hungary.
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24
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Salminen A, Haapasalo A, Kauppinen A, Kaarniranta K, Soininen H, Hiltunen M. Impaired mitochondrial energy metabolism in Alzheimer's disease: Impact on pathogenesis via disturbed epigenetic regulation of chromatin landscape. Prog Neurobiol 2015; 131:1-20. [PMID: 26001589 DOI: 10.1016/j.pneurobio.2015.05.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 05/05/2015] [Accepted: 05/11/2015] [Indexed: 12/14/2022]
Abstract
The amyloid cascade hypothesis for the pathogenesis of Alzheimer's disease (AD) was proposed over twenty years ago. However, the mechanisms of neurodegeneration and synaptic loss have remained elusive delaying the effective drug discovery. Recent studies have revealed that amyloid-β peptides as well as phosphorylated and fragmented tau proteins accumulate within mitochondria. This process triggers mitochondrial fission (fragmentation) and disturbs Krebs cycle function e.g. by inhibiting the activity of 2-oxoglutarate dehydrogenase. Oxidative stress, hypoxia and calcium imbalance also disrupt the function of Krebs cycle in AD brains. Recent studies on epigenetic regulation have revealed that Krebs cycle intermediates control DNA and histone methylation as well as histone acetylation and thus they have fundamental roles in gene expression. DNA demethylases (TET1-3) and histone lysine demethylases (KDM2-7) are included in the family of 2-oxoglutarate-dependent oxygenases (2-OGDO). Interestingly, 2-oxoglutarate is the obligatory substrate of 2-OGDO enzymes, whereas succinate and fumarate are the inhibitors of these enzymes. Moreover, citrate can stimulate histone acetylation via acetyl-CoA production. Epigenetic studies have revealed that AD is associated with changes in DNA methylation and histone acetylation patterns. However, the epigenetic results of different studies are inconsistent but one possibility is that they represent both coordinated adaptive responses and uncontrolled stochastic changes, which provoke pathogenesis in affected neurons. Here, we will review the changes observed in mitochondrial dynamics and Krebs cycle function associated with AD, and then clarify the mechanisms through which mitochondrial metabolites can control the epigenetic landscape of chromatin and induce pathological changes in AD.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland.
| | - Annakaisa Haapasalo
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Hilkka Soininen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland
| | - Mikko Hiltunen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 100, FI-70029 KYS, Finland; Institute of Biomedicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland
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25
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Diaz-Muñoz MD, Bell SE, Fairfax K, Monzon-Casanova E, Cunningham AF, Gonzalez-Porta M, Andrews SR, Bunik VI, Zarnack K, Curk T, Heggermont WA, Heymans S, Gibson GE, Kontoyiannis DL, Ule J, Turner M. The RNA-binding protein HuR is essential for the B cell antibody response. Nat Immunol 2015; 16:415-25. [PMID: 25706746 PMCID: PMC4479220 DOI: 10.1038/ni.3115] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 01/28/2015] [Indexed: 12/26/2022]
Abstract
Post-transcriptional regulation of mRNA by the RNA-binding protein HuR (encoded by Elavl1) is required in B cells for the germinal center reaction and for the production of class-switched antibodies in response to thymus-independent antigens. Transcriptome-wide examination of RNA isoforms and their abundance and translation in HuR-deficient B cells, together with direct measurements of HuR-RNA interactions, revealed that HuR-dependent splicing of mRNA affected hundreds of transcripts, including that encoding dihydrolipoamide S-succinyltransferase (Dlst), a subunit of the 2-oxoglutarate dehydrogenase (α-KGDH) complex. In the absence of HuR, defective mitochondrial metabolism resulted in large amounts of reactive oxygen species and B cell death. Our study shows how post-transcriptional processes control the balance of energy metabolism required for the proliferation and differentiation of B cells.
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Affiliation(s)
- Manuel D Diaz-Muñoz
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK
| | - Sarah E Bell
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK
| | - Kirsten Fairfax
- 1] Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK. [2] The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Elisa Monzon-Casanova
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK
| | - Adam F Cunningham
- MRC Centre for Immune Regulation, Institute of Microbiology and Infection, School of Immunity and Infection, University of Birmingham, Birmingham, UK
| | - Mar Gonzalez-Porta
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Cambridge, UK
| | | | - Victoria I Bunik
- A. N. Belozersky Institute of PhysicoChemical Biology and Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences, Frankfurt, Germany
| | - Tomaž Curk
- University of Ljubljana, Faculty of Computer and Information Science, Ljubljana, Slovenia
| | | | - Stephane Heymans
- 1] Center for Molecular and Vascular Biology, KU Leuven, Belgium. [2] Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands
| | - Gary E Gibson
- Weill Cornell Medical College, Brain and Mind Research Institute, Burke Medical Research Institute, White Plains, New York, USA
| | - Dimitris L Kontoyiannis
- Division of Immunology, Biomedical Sciences Research Center "Alexander Fleming", Vari, Greece
| | - Jernej Ule
- UCL Genetics Institute, Department of Genetics, Environment and Evolution, University College London, London, UK
| | - Martin Turner
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Cambridge, UK
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26
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Nemeria NS, Ambrus A, Patel H, Gerfen G, Adam-Vizi V, Tretter L, Zhou J, Wang J, Jordan F. Human 2-oxoglutarate dehydrogenase complex E1 component forms a thiamin-derived radical by aerobic oxidation of the enamine intermediate. J Biol Chem 2014; 289:29859-73. [PMID: 25210035 DOI: 10.1074/jbc.m114.591073] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Herein are reported unique properties of the human 2-oxoglutarate dehydrogenase multienzyme complex (OGDHc), a rate-limiting enzyme in the Krebs (citric acid) cycle. (a) Functionally competent 2-oxoglutarate dehydrogenase (E1o-h) and dihydrolipoyl succinyltransferase components have been expressed according to kinetic and spectroscopic evidence. (b) A stable free radical, consistent with the C2-(C2α-hydroxy)-γ-carboxypropylidene thiamin diphosphate (ThDP) cation radical was detected by electron spin resonance upon reaction of the E1o-h with 2-oxoglutarate (OG) by itself or when assembled from individual components into OGDHc. (c) An unusual stability of the E1o-h-bound C2-(2α-hydroxy)-γ-carboxypropylidene thiamin diphosphate (the "ThDP-enamine"/C2α-carbanion, the first postdecarboxylation intermediate) was observed, probably stabilized by the 5-carboxyl group of OG, not reported before. (d) The reaction of OG with the E1o-h gave rise to superoxide anion and hydrogen peroxide (reactive oxygen species (ROS)). (e) The relatively stable enzyme-bound enamine is the likely substrate for oxidation by O2, leading to the superoxide anion radical (in d) and the radical (in b). (f) The specific activity assessed for ROS formation compared with the NADH (overall complex) activity, as well as the fraction of radical intermediate occupying active centers of E1o-h are consistent with each other and indicate that radical/ROS formation is an "off-pathway" side reaction comprising less than 1% of the "on-pathway" reactivity. However, the nearly ubiquitous presence of OGDHc in human tissues, including the brain, makes these findings of considerable importance in human metabolism and perhaps disease.
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Affiliation(s)
- Natalia S Nemeria
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Attila Ambrus
- the Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest 1094, Hungary, and
| | - Hetalben Patel
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Gary Gerfen
- the Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Vera Adam-Vizi
- the Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest 1094, Hungary, and
| | - Laszlo Tretter
- the Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest 1094, Hungary, and
| | - Jieyu Zhou
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Junjie Wang
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Frank Jordan
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102,
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Rettberg JR, Yao J, Brinton RD. Estrogen: a master regulator of bioenergetic systems in the brain and body. Front Neuroendocrinol 2014; 35:8-30. [PMID: 23994581 PMCID: PMC4024050 DOI: 10.1016/j.yfrne.2013.08.001] [Citation(s) in RCA: 305] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/09/2013] [Accepted: 08/10/2013] [Indexed: 01/12/2023]
Abstract
Estrogen is a fundamental regulator of the metabolic system of the female brain and body. Within the brain, estrogen regulates glucose transport, aerobic glycolysis, and mitochondrial function to generate ATP. In the body, estrogen protects against adiposity, insulin resistance, and type II diabetes, and regulates energy intake and expenditure. During menopause, decline in circulating estrogen is coincident with decline in brain bioenergetics and shift towards a metabolically compromised phenotype. Compensatory bioenergetic adaptations, or lack thereof, to estrogen loss could determine risk of late-onset Alzheimer's disease. Estrogen coordinates brain and body metabolism, such that peripheral metabolic state can indicate bioenergetic status of the brain. By generating biomarker profiles that encompass peripheral metabolic changes occurring with menopause, individual risk profiles for decreased brain bioenergetics and cognitive decline can be created. Biomarker profiles could identify women at risk while also serving as indicators of efficacy of hormone therapy or other preventative interventions.
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Affiliation(s)
- Jamaica R Rettberg
- Neuroscience Department, University of Southern California, Los Angeles, CA 90033, United States
| | - Jia Yao
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States
| | - Roberta Diaz Brinton
- Neuroscience Department, University of Southern California, Los Angeles, CA 90033, United States; Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, United States; Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, United States.
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29
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Raukas M, Rebane R, Mahlapuu R, Jefremov V, Zilmer K, Karelson E, Bogdanovic N, Zilmer M. Mitochondrial oxidative stress index, activity of redox-sensitive aconitase and effects of endogenous anti- and pro-oxidants on its activity in control, Alzheimer's disease and Swedish Familial Alzheimer's disease brain. Free Radic Res 2012; 46:1490-5. [DOI: 10.3109/10715762.2012.728286] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Gibson GE, Hirsch JA, Cirio RT, Jordan BD, Fonzetti P, Elder J. Abnormal thiamine-dependent processes in Alzheimer's Disease. Lessons from diabetes. Mol Cell Neurosci 2012; 55:17-25. [PMID: 22982063 DOI: 10.1016/j.mcn.2012.09.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 01/30/2023] Open
Abstract
Reduced glucose metabolism is an invariant feature of Alzheimer's Disease (AD) and an outstanding biomarker of disease progression. Glucose metabolism may be an attractive therapeutic target, whether the decline initiates AD pathophysiology or is a critical component of a cascade. The cause of cerebral regional glucose hypometabolism remains unclear. Thiamine-dependent processes are critical in glucose metabolism and are diminished in brains of AD patients at autopsy. Further, the reductions in thiamine-dependent processes are highly correlated to the decline in clinical dementia rating scales. In animal models, thiamine deficiency exacerbates plaque formation, promotes phosphorylation of tau and impairs memory. In contrast, treatment of mouse models of AD with the thiamine derivative benfotiamine diminishes plaques, decreases phosphorylation of tau and reverses memory deficits. Diabetes predisposes to AD, which suggests they may share some common mechanisms. Benfotiamine diminishes peripheral neuropathy in diabetic humans and animals. In diabetes, benfotiamine induces key thiamine-dependent enzymes of the pentose shunt to reduce accumulation of toxic metabolites including advanced glycation end products (AGE). Related mechanisms may lead to reversal of plaque formation by benfotiamine in animals. If so, the use of benfotiamine could provide a safe intervention to reverse biological and clinical processes of AD progression. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
- Gary E Gibson
- Department of Neurology and Neuroscience, Weill Cornell Medical College, Burke Medical Research Institute, 785 Mamaroneck Avenue, White Plains, NY 10605, USA.
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Starkov AA. An update on the role of mitochondrial α-ketoglutarate dehydrogenase in oxidative stress. Mol Cell Neurosci 2012; 55:13-6. [PMID: 22820180 DOI: 10.1016/j.mcn.2012.07.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 06/22/2012] [Accepted: 07/10/2012] [Indexed: 01/06/2023] Open
Abstract
The activity of mitochondrial alpha-ketoglutarate dehydrogenase complex (KGDHC) is severely reduced in human pathologies where oxidative stress is traditionally thought to play an important role, such as familial and sporadic forms of Alzheimer's disease and other age-related neurodegenerative diseases. This minireview is focused on substantial data that were accumulated over the last 2 decades to support the concept that KGDHC can be a primary mitochondrial target of oxidative stress and at the same time a key contributor to it by producing reactive oxygen species. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
- Anatoly A Starkov
- Department of Neurology and Neuroscience, Weill Medical College, Cornell University, New York, NY 10021, USA.
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32
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Kinetic Modeling of the Mitochondrial Energy Metabolism of Neuronal Cells: The Impact of Reduced α-Ketoglutarate Dehydrogenase Activities on ATP Production and Generation of Reactive Oxygen Species. Int J Cell Biol 2012; 2012:757594. [PMID: 22719765 PMCID: PMC3376505 DOI: 10.1155/2012/757594] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 04/11/2012] [Indexed: 11/17/2022] Open
Abstract
Reduced activity of brain α-ketoglutarate dehydrogenase complex (KGDHC) occurs in a number of neurodegenerative diseases like Parkinson's disease and Alzheimer's disease. In order to quantify the relation between diminished KGDHC activity and the mitochondrial ATP generation, redox state, transmembrane potential, and generation of reactive oxygen species (ROS) by the respiratory chain (RC), we developed a detailed kinetic model. Model simulations revealed a threshold-like decline of the ATP production rate at about 60% inhibition of KGDHC accompanied by a significant increase of the mitochondrial membrane potential. By contrast, progressive inhibition of the enzyme aconitase had only little impact on these mitochondrial parameters. As KGDHC is susceptible to ROS-dependent inactivation, we also investigated the reduction state of those sites of the RC proposed to be involved in ROS production. The reduction state of all sites except one decreased with increasing degree of KGDHC inhibition suggesting an ROS-reducing effect of KGDHC inhibition. Our model underpins the important role of reduced KGDHC activity in the energetic breakdown of neuronal cells during development of neurodegenerative diseases.
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33
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Dumont M, Beal MF. Neuroprotective strategies involving ROS in Alzheimer disease. Free Radic Biol Med 2011; 51:1014-26. [PMID: 21130159 PMCID: PMC3070183 DOI: 10.1016/j.freeradbiomed.2010.11.026] [Citation(s) in RCA: 262] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 10/29/2010] [Accepted: 11/22/2010] [Indexed: 12/14/2022]
Abstract
Alzheimer disease (AD) is a neurodegenerative disorder in which oxidative stress is a key hallmark. It occurs early in disease pathogenesis and can exacerbate its progression. Several causes of oxidative stress have been determined over the years. First, mitochondria play an important role in the generation and accumulation of free radicals. In addition to mitochondria, inflammation can also induce oxidative damage, especially via microglia, and microglia are also important for Aβ clearance. In AD, both mitochondrial function and inflammatory response are affected, leading to increased ROS formation and oxidative damage to lipid, proteins, and nucleic acids. Some other sources have also been identified. From these findings, various neuroprotective strategies against ROS-mediated damages have been elaborated in AD research. This review recapitulates some of the major strategies used to prevent oxidative stress and disease progression. Outcomes from in vitro and in vivo studies using models of AD are encouraging. However, only a few clinical trials have provided positive results in terms of slowing down cognitive decline. Nonetheless, there is still hope for improved compounds that would better target pathways implicated in ROS production. In fact, facilitating the endogenous antioxidant system by modulating transcription has great promise for AD therapy.
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Affiliation(s)
- Magali Dumont
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA.
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34
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Readnower RD, Sauerbeck AD, Sullivan PG. Mitochondria, Amyloid β, and Alzheimer's Disease. Int J Alzheimers Dis 2011; 2011:104545. [PMID: 21547208 PMCID: PMC3087417 DOI: 10.4061/2011/104545] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 01/25/2011] [Indexed: 01/04/2023] Open
Abstract
Hypometabolism is a hallmark of Alzheimer's disease (AD) and implicates a mitochondrial role in the neuropathology associated with AD. Mitochondrial amyloid-beta (Aβ) accumulation precedes extracellular Aβ deposition. In addition to increasing oxidative stress, Aβ has been shown to directly inhibit mitochondrial enzymes. Inhibition of mitochondrial enzymes as a result of oxidative damage or Aβ interaction perpetuates oxidative stress and leads to a hypometabolic state. Additionally, Aβ has also been shown to interact with cyclophilin D, a component of the mitochondrial permeability transition pore, which may promote cell death. Therefore, ample evidence exists indicating that the mitochondrion plays a vital role in the pathophysiology observed in AD.
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Affiliation(s)
- Ryan D Readnower
- Spinal Cord & Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA
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35
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Large-scale in silico modeling of metabolic interactions between cell types in the human brain. Nat Biotechnol 2010; 28:1279-85. [PMID: 21102456 PMCID: PMC3140076 DOI: 10.1038/nbt.1711] [Citation(s) in RCA: 187] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Metabolic interactions between multiple cell types are difficult to model using existing approaches. Here we present a workflow that integrates gene expression data, proteomics data and literature-based manual curation to model human metabolism within and between different types of cells. Transport reactions are used to account for the transfer of metabolites between models of different cell types via the interstitial fluid. We apply the method to create models of brain energy metabolism that recapitulate metabolic interactions between astrocytes and various neuron types relevant to Alzheimer's disease. Analysis of the models identifies genes and pathways that may explain observed experimental phenomena, including the differential effects of the disease on cell types and regions of the brain. Constraint-based modeling can thus contribute to the study and analysis of multicellular metabolic processes in the human tissue microenvironment and provide detailed mechanistic insight into high-throughput data analysis.
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36
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Hurko O, Boudonck K, Gonzales C, Hughes ZA, Jacobsen JS, Reinhart PH, Crowther D. Ablation of the locus coeruleus increases oxidative stress in tg-2576 transgenic but not wild-type mice. Int J Alzheimers Dis 2010; 2010:864625. [PMID: 20981353 PMCID: PMC2958341 DOI: 10.4061/2010/864625] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 08/23/2010] [Accepted: 09/03/2010] [Indexed: 11/20/2022] Open
Abstract
Mice transgenic for production of excessive or mutant forms of beta-amyloid differ from patients with Alzheimer's disease in the degree of inflammation, oxidative damage, and alteration of intermediary metabolism, as well as the paucity or absence of neuronal atrophy and cognitive impairment. Previous observers have suggested that differences in inflammatory response reflect a discrepancy in the state of the locus coeruleus (LC), loss of which is an early change in Alzheimer's disease but which is preserved in the transgenic mice. In this paper, we extend these observations by examining the effects of the LC on markers of oxidative stress and intermediary metabolism. We compare four groups: wild-type or Tg2576 Aβ transgenic mice injected with DSP4 or vehicle. Of greatest interest were metabolites different between ablated and intact transgenics, but not between ablated and intact wild-type animals. The Tg2576_DSP4 mice were distinguished from the other three groups by oxidative stress and altered energy metabolism. These observations provide further support for the hypothesis that Tg2576 Aβ transgenic mice with this ablation may be a more congruent model of Alzheimer's disease than are transgenics with an intact LC.
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Affiliation(s)
- Orest Hurko
- Biologics Consulting Group, Inc., 400 N. Washington Street, Suite 100, Alexandria, VA 22314, USA
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37
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Dumont M, Lin MT, Beal MF. Mitochondria and antioxidant targeted therapeutic strategies for Alzheimer's disease. J Alzheimers Dis 2010; 20 Suppl 2:S633-43. [PMID: 20421689 DOI: 10.3233/jad-2010-100507] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Oxidative stress and mitochondrial dysfunction are important features present in Alzheimer's disease (AD). They appear early and contribute to disease progression, both in human postmortem AD brains as well as in transgenic AD mouse brains. For this reason, targeting oxidative stress and mitochondria in AD may lead to the development of promising therapeutic strategies. Several exogenous antioxidant compounds have been tested and found beneficial in transgenic AD mice, such as vitamins and spices. However, their efficacy was much more modest in human trials. More recently, new strategies have been elaborated to promote endogenous antioxidant systems. Different pathways involved in oxidative stress response have been identified. Compounds able to upregulate these pathways are being generated and tested in animal models of AD and in human patients. Upregulation of antioxidant gene expression was beneficial in mice, giving hope for future avenues in the treatment of AD and other neurodegenerative disorders.
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Affiliation(s)
- Magali Dumont
- Weill Cornell Medical College, Department of Neurology and Neuroscience, New York, NY, USA
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38
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Galindo MF, Ikuta I, Zhu X, Casadesus G, Jordán J. Mitochondrial biology in Alzheimer's disease pathogenesis. J Neurochem 2010; 114:933-45. [PMID: 20492350 DOI: 10.1111/j.1471-4159.2010.06814.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite the increasing knowledge of Alzheimer's disease (AD) management with novel pharmacologic agents, most of them are only transiently fixing symptomatic pathology. Currently there is rapid growth in the field of neuroprotective pharmacology and increasing focus on the involvement of mitochondria in this devastating disease. This review is directed at understanding the role of mitochondria-mediated pathways in AD and integrating basic biology of the mitochondria with knowledge of possible pharmacologic targets for AD treatment in an attempt to elucidate novel mitochondria-driven therapeutic interventions useful to both clinical and basic research.
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Affiliation(s)
- María F Galindo
- Unidad de Neuropsicofarmacología Translacional, Complejo Hospitalario Universitario de Albacete, Albacete, Spain
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39
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Alikhani N, Ankarcrona M, Glaser E. Mitochondria and Alzheimer's disease: amyloid-beta peptide uptake and degradation by the presequence protease, hPreP. J Bioenerg Biomembr 2010; 41:447-51. [PMID: 19798557 DOI: 10.1007/s10863-009-9244-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Several lines of evidence suggest mitochondrial dysfunction as a possible underlying mechanism of Alzheimer's disease (AD). Accumulation of the amyloid-beta peptide (Abeta), a neurotoxic peptide implicated in the pathogenesis of AD, has been detected in brain mitochondria of AD patients and AD transgenic mouse models. In vitro evidence suggests that the Abeta causes mitochondrial dysfunction e.g. oxidative stress, mitochondrial fragmentation and decreased activity of cytochrome c oxidase and TCA cycle enzymes. Here we review the link between mitochondrial dysfunctions and AD. In particular we focus on the mechanism for Abeta uptake by mitochondria and on the recently identified Abeta degrading protease in human brain mitochondria.
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Affiliation(s)
- Nyosha Alikhani
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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40
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VDAC, a multi-functional mitochondrial protein regulating cell life and death. Mol Aspects Med 2010; 31:227-85. [PMID: 20346371 DOI: 10.1016/j.mam.2010.03.002] [Citation(s) in RCA: 530] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 03/17/2010] [Indexed: 01/22/2023]
Abstract
Research over the past decade has extended the prevailing view of the mitochondrion to include functions well beyond the generation of cellular energy. It is now recognized that mitochondria play a crucial role in cell signaling events, inter-organellar communication, aging, cell proliferation, diseases and cell death. Thus, mitochondria play a central role in the regulation of apoptosis (programmed cell death) and serve as the venue for cellular decisions leading to cell life or death. One of the mitochondrial proteins controlling cell life and death is the voltage-dependent anion channel (VDAC), also known as mitochondrial porin. VDAC, located in the mitochondrial outer membrane, functions as gatekeeper for the entry and exit of mitochondrial metabolites, thereby controlling cross-talk between mitochondria and the rest of the cell. VDAC is also a key player in mitochondria-mediated apoptosis. Thus, in addition to regulating the metabolic and energetic functions of mitochondria, VDAC appears to be a convergence point for a variety of cell survival and cell death signals mediated by its association with various ligands and proteins. In this article, we review what is known about the VDAC channel in terms of its structure, relevance to ATP rationing, Ca(2+) homeostasis, protection against oxidative stress, regulation of apoptosis, involvement in several diseases and its role in the action of different drugs. In light of our recent findings and the recently solved NMR- and crystallography-based 3D structures of VDAC1, the focus of this review will be on the central role of VDAC in cell life and death, addressing VDAC function in the regulation of mitochondria-mediated apoptosis with an emphasis on structure-function relations. Understanding structure-function relationships of VDAC is critical for deciphering how this channel can perform such a variety of functions, all important for cell life and death. This review also provides insight into the potential of VDAC1 as a rational target for new therapeutics.
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41
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Dumont M, Ho DJ, Calingasan NY, Xu H, Gibson G, Beal MF. Mitochondrial dihydrolipoyl succinyltransferase deficiency accelerates amyloid pathology and memory deficit in a transgenic mouse model of amyloid deposition. Free Radic Biol Med 2009; 47:1019-27. [PMID: 19596066 PMCID: PMC2761144 DOI: 10.1016/j.freeradbiomed.2009.07.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 07/06/2009] [Accepted: 07/07/2009] [Indexed: 12/20/2022]
Abstract
Mitochondrial dysfunction and oxidative stress are involved in Alzheimer disease (AD) pathogenesis. In human AD brains, the activity of the alpha-ketoglutarate dehydrogenase enzyme complex (alpha-KGDHC) is reduced. KGDHC is mostly involved in NADH production. It can also participate in oxidative stress and reactive oxygen species (ROS) production. The mitochondrial dihydrolipoyl succinyltransferase enzyme (DLST) is a key subunit specific to the alpha-KGDHC. In cultured cells, reduction of DLST increased H(2)O(2)-induced ROS generation and cell death. Thus, we asked whether partial genetic deletion of DLST could accelerate the onset of AD pathogenesis, using a transgenic mouse model of amyloid deposition crossed with DLST(+/-) mice. Tg19959 mice, which carry the human amyloid precursor protein with two mutations, develop amyloid deposits and progressive behavioral abnormalities. We compared Tg19959 mice to Tg19959-DLST(+/-) littermates at 2-3 months of age and studied the effects of DLST deficiency on amyloid deposition, spatial learning and memory, and oxidative stress. We found that alpha-KGDHC activity was reduced in DLST(+/-) mice. We also found that DLST deficiency increased amyloid plaque burden, Abeta oligomers, and nitrotyrosine levels and accelerated the occurrence of spatial learning and memory deficits in female Tg19959 mice. Our data suggest that alpha-KGDHC may be involved in AD pathogenesis through increased mitochondrial oxidative stress.
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Affiliation(s)
- Magali Dumont
- Department of Neurology and Neuroscience, Weill Cornell Medical College,New York, NY 10065, USA.
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42
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Gibson GE, Starkov A, Blass JP, Ratan RR, Beal MF. Cause and consequence: mitochondrial dysfunction initiates and propagates neuronal dysfunction, neuronal death and behavioral abnormalities in age-associated neurodegenerative diseases. Biochim Biophys Acta Mol Basis Dis 2009; 1802:122-34. [PMID: 19715758 DOI: 10.1016/j.bbadis.2009.08.010] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 08/14/2009] [Accepted: 08/17/2009] [Indexed: 12/31/2022]
Abstract
Age-related neurodegenerative diseases are associated with mild impairment of oxidative metabolism and accumulation of abnormal proteins. Within the cell, the mitochondria appears to be a dominant site for initiation and propagation of disease processes. Shifts in metabolism in response to mild metabolic perturbations may decrease the threshold for irreversible injury in response to ordinarily sublethal metabolic insults. Mild impairment of metabolism accrue from and lead to increased reactive oxygen species (ROS). Increased ROS change cell signaling via post-transcriptional and transcriptional changes. The cause and consequences of mild impairment of mitochondrial metabolism is one focus of this review. Many experiments in tissues from humans support the notion that oxidative modification of the alpha-ketoglutarate dehydrogenase complex (KGDHC) compromises neuronal energy metabolism and enhances ROS production in Alzheimer's Disease (AD). These data suggest that cognitive decline in AD derives from the selective tricarboxylic acid (TCA) cycle abnormalities. By contrast in Huntington's Disease (HD), a movement disorder with cognitive features distinct form AD, complex II+III abnormalities may dominate. These distinct mitochondrial abnormalities culminate in oxidative stress, energy dysfunction, and aberrant homeostasis of cytosolic calcium. Cytosolic calcium, elevations even only transiently, leads to hyperactivity of a number of enzymes. One calcium-activated enzyme with demonstrated pathophysiological import in HD and AD is transglutaminase (TGase). TGase is a crosslinking enzymes that can modulate transcription, inactivate metabolic enzymes, and cause aggregation of critical proteins. Recent data indicate that TGase can silence expression of genes involved in compensating for metabolic stress. Altogether, our results suggest that increasing KGDHC via inhibition of TGase or via a host of other strategies to be described would be effective therapeutic approaches in age-associated neurodegenerative diseases.
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Affiliation(s)
- Gary E Gibson
- Department of Neurology and Neuroscience, Weill Cornell Medical College of Cornell University at Burke Medical Research Institute, 785 Mamaroneck Avenue, White Plains, NY 10605, USA.
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43
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Studzinski CM, MacKay WA, Beckett TL, Henderson ST, Murphy MP, Sullivan PG, Burnham WM. Induction of ketosis may improve mitochondrial function and decrease steady-state amyloid-β precursor protein (APP) levels in the aged dog. Brain Res 2008; 1226:209-17. [DOI: 10.1016/j.brainres.2008.06.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Revised: 06/03/2008] [Accepted: 06/03/2008] [Indexed: 01/06/2023]
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44
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Translocation of amyloid precursor protein C-terminal fragment(s) to the nucleus precedes neuronal death due to thiamine deficiency-induced mild impairment of oxidative metabolism. Neurochem Res 2008; 33:1365-72. [PMID: 18317926 DOI: 10.1007/s11064-008-9594-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Accepted: 01/10/2008] [Indexed: 10/22/2022]
Abstract
Thiamine deficiency (TD) is a model of neurodegeneration induced by mild impairment of oxidative metabolism. TD produces time-dependent glial activation, inflammation, oxidative stress, altered metabolism of amyloid precursor protein (APP), exacerbation of plaque formation from APP, and finally, selective neuron death in specific brain regions. The sub-medial thalamic nucleus (SmTN) is the most sensitive region to TD. Alteration in APP metabolism and nuclear translocation of carboxy-terminal fragments (CTF) of APP has been implicated in neuron death in other models of neurodegeneration. These experiments tested whether TD causes translocation of CTF into the nucleus of neurons in the SmTN that are destined to die after 9 days of TD by examining overlapping immunoreactivity (IR) of antibody APP 369 with either Alz90, 6E10 or 4G8 epitopes in the nuclei of the neurons in the SmTN. TD caused the accumulation of the CTF of APP in nuclei of SmTN neurons within 3 days of TD. These changes did not occur in the cortex which is spared in TD. Western blot analysis of nuclear fractions revealed a significant (61%; P < 0.026) increase in CTF 12 levels in TD SmTN (2.08 +/- 0.56) compared to control SmTN (1.29 +/- 0.41). Although TD increased CTF 15 levels in TD SmTN (1.95 +/- 0.73) compared to control SmTN (0.62 +/- 0.52) by 214%; P < 0.665 and decreased the full-length holo-APP levels in TD SmTN (0.32 +/- 0.30) compared to control SmTN (0.47 +/- 0.18) by 34%; P < 0.753, the differences were statistically insignificant. TD did not alter CTF 15 or CTF 12 levels in cortex. These findings demonstrate that changes in APP metabolism occur in early stages of TD, and they may play an important role in TD-induced selective neuronal loss.
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45
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Shi Q, Xu H, Kleinman WA, Gibson GE. Novel functions of the alpha-ketoglutarate dehydrogenase complex may mediate diverse oxidant-induced changes in mitochondrial enzymes associated with Alzheimer's disease. Biochim Biophys Acta Mol Basis Dis 2007; 1782:229-38. [PMID: 18206986 DOI: 10.1016/j.bbadis.2007.12.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 12/07/2007] [Accepted: 12/12/2007] [Indexed: 12/13/2022]
Abstract
Measures in autopsied brains from Alzheimer's Disease (AD) patients reveal a decrease in the activity of alpha-ketoglutarate dehydrogenase complex (KGDHC) and an increase in malate dehydrogenase (MDH) activity. The present experiments tested whether both changes could be caused by the common oxidant H(2)O(2) and to probe the mechanism underlying these changes. Since the response to H(2)O(2) is modified by the level of the E2k subunit of KGDHC, the interaction of MDH and KGDHC was studied in cells with varying levels of E2k. In cells with only 23% of normal E2k protein levels, one-hour treatment with H(2)O(2) decreased KGDHC and increased MDH activity as well as the mRNA level for both cytosolic and mitochondrial MDH. The increase in MDH did not occur in cells with 100% or 46% of normal E2k. Longer treatments with H(2)O(2) inhibited the activity of both enzymes. Glutathione is a major regulator of cellular redox state and can modify enzyme activities. H(2)O(2) converts reduced glutathione (GSH) to oxidized glutathione (GSSG), which reacts with protein thiols. Treatment of purified KGDHC with GSSG leads to glutathionylation of all three KGDHC subunits. Thus, cellular glutathione level was manipulated by two means to determine the effect on KGDHC and MDH activities. Both buthionine sulfoximine (BSO), which inhibits glutathione synthesis without altering redox state, and H(2)O(2) diminished glutathione to a similar level after 24 h. However, H(2)O(2), but not BSO, reduced KGDHC and MDH activities, and the reduction was greater in the E2k-23 line. These findings suggest that the E2k may mediate diverse responses of KGDHC and MDH to oxidants. In addition, the differential response of activities to BSO and H(2)O(2) together with the in vitro interaction of KGDHC with GSSG suggests that glutathionylation is one possible mechanism underlying oxidative stress-induced inhibition of the TCA cycle enzymes.
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Affiliation(s)
- Qingli Shi
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University/Burke Medical Research Institute, White Plains, New York 10605, USA
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46
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Abstract
As an important molecule in the pathogenesis of Alzheimer's disease (AD), amyloid-beta (Abeta) interferes with multiple aspects of mitochondrial function, including energy metabolism failure, production of reactive oxygen species (ROS) and permeability transition pore formation. Recent studies have demonstrated that Abeta progressively accumulates within mitochondrial matrix, providing a direct link to mitochondrial toxicity. Abeta-binding alcohol dehydrogenase (ABAD) is localized to the mitochondrial matrix and binds to mitochondrial Abeta. Interaction of ABAD with Abeta exaggerates Abeta-mediated mitochondrial and neuronal perturbation, leading to impaired synaptic function, and dysfunctional spatial learning/memory. Thus, blockade of ABAD/Abeta interaction may be a potential therapeutic strategy for AD.
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Affiliation(s)
- John Xi Chen
- Harvey Cushing Institutes of Neuroscience, North Shore-Long Island Jewish Health System, Great Neck, NY 11021, USA
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Abstract
Reductions in brain glucose metabolism and increased oxidative stress invariably occur in Alzheimer's disease (AD) and thiamine (vitamin B1) deficiency. Both conditions cause irreversible cognitive impairment; their behavioral consequences overlap but are not identical. Thiamine-dependent processes are critical in glucose metabolism, and recent studies implicate thiamine in oxidative stress, protein processing, peroxisomal function, and gene expression. The activities of thiamine-dependent enzymes are characteristically diminished in AD, and the reductions in autopsy AD brain correlate highly with the extent of dementia in the preagonal state. Abnormalities in thiamine-dependent processes can be plausibly linked to the pathology of AD. Seemingly paradoxical properties of thiamine-dependent processes may underlie their relation to the pathophysiology of AD: Reduction of thiamine-dependent processes increase oxidative stress. Thiamine can act as a free radical scavenger. Thiamine-dependent mitochondrial dehydrogenase complexes produce oxygen free radicals and are sensitive to oxidative stress. Genetic disorders of thiamine metabolism that lead to neurological disease can be treated with large doses of thiamine. Although thiamine itself has not shown dramatic benefits in AD patients, the available data is scanty. Adding thiamine or more absorbable forms of thiamine to tested treatments for the abnormality in glucose metabolism in AD may increase their efficacy.
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Affiliation(s)
- Gary E Gibson
- Department of Neurology and Neurosciences, Weill Medical College of Cornell University, Burke Medical Research Institute, White Plains, New York 10605, USA.
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Opii WO, Nukala VN, Sultana R, Pandya JD, Day KM, Merchant ML, Klein JB, Sullivan PG, Butterfield DA. Proteomic identification of oxidized mitochondrial proteins following experimental traumatic brain injury. J Neurotrauma 2007; 24:772-89. [PMID: 17518533 DOI: 10.1089/neu.2006.0229] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Experimental traumatic brain injury (TBI) results in a significant loss of cortical tissue at the site of injury, and in the ensuing hours and days a secondary injury exacerbates this primary injury, resulting in significant neurological dysfunction. The mechanism of the secondary injury is not well understood, but evidence implicates a critical role for mitochondria in this cascade. This mitochondrial dysfunction is believed to involve excitotoxicity, disruption of Ca(2+) homeostasis, production of reactive oxygen species (ROS), ATP depletion, oxidative damage of mitochondrial proteins, and an overall breakdown of mitochondrial bioenergetics. Although oxidative damage occurs following TBI, the identities of proteins undergoing oxidative modification after TBI have not been investigated. In the present study, we utilized the 3-h post-injury controlled cortical impact model of experimental TBI in 20 young adult male Sprague-Dawley rats, coupled with proteomics to identify specific mitochondrial fraction proteins from the cortex and hippocampus that were oxidatively modified after TBI. We identified, from the cortex, pyruvate dehydrogenase, voltage-dependent anion channel, fumarate hydratase 1, ATP synthase, and prohibitin. From the hippocampus, we identified cytochrome C oxidase Va, isovaleryl coenzyme A dehydrogenase, enolase-1, and glyceraldehyde-3-phosphate dehydrogenase as proteins that had undergone oxidative modification following TBI. In addition, we have also shown that, following TBI, there is a reduction in the activities of pyruvate dehydrogenase (PDH), complex I, and complex IV. These findings demonstrate that, following TBI, several proteins involved in mitochondrial bioenergetics are highly oxidatively modified, which may possibly underlie the massive breakdown of mitochondrial energetics and eventual cell death known to occur in this model. The identification of these proteins provides new insights into the mechanisms that take place following TBI and may provide avenues for possible therapeutic interventions after TBI.
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Affiliation(s)
- Wycliffe O Opii
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA
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Chang DTW, Reynolds IJ. Mitochondrial trafficking and morphology in healthy and injured neurons. Prog Neurobiol 2006; 80:241-68. [PMID: 17188795 DOI: 10.1016/j.pneurobio.2006.09.003] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 09/14/2006] [Accepted: 09/18/2006] [Indexed: 12/21/2022]
Abstract
Mitochondria are the primary generators of ATP and are important regulators of intracellular calcium homeostasis. These organelles are dynamically transported along lengthy neuronal processes, presumably for appropriate distribution to cellular regions of high metabolic demand and elevated intracellular calcium, such as synapses. The removal of damaged mitochondria that produce harmful reactive oxygen species and promote apoptosis is also thought to be mediated by transport of mitochondria to autophagosomes. Mitochondrial trafficking is therefore important for maintaining neuronal and mitochondrial health while cessation of movement may lead to neuronal and mitochondrial dysfunction. Mitochondrial morphology is also dynamic and is remodeled during neuronal injury and disease. Recent studies reveal different manifestations and mechanisms of impaired mitochondrial movement and altered morphology in injured neurons. These are likely to cause varied courses toward neuronal degeneration and death. The goal of this review is to provide an appreciation of the full range of mitochondrial function, morphology and trafficking, and the critical role these parameters play in neuronal physiology and pathophysiology.
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Affiliation(s)
- Diane T W Chang
- Medical Scientist Training Program, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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50
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Smolle M, Prior AE, Brown AE, Cooper A, Byron O, Lindsay JG. A new level of architectural complexity in the human pyruvate dehydrogenase complex. J Biol Chem 2006; 281:19772-80. [PMID: 16679318 PMCID: PMC3954457 DOI: 10.1074/jbc.m601140200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian pyruvate dehydrogenase multienzyme complex (PDC) is a key metabolic assembly comprising a 60-meric pentagonal dodecahedral E2 (dihydrolipoamide acetyltransferase) core attached to which are 30 pyruvate decarboxylase E1 heterotetramers and 6 dihydrolipoamide dehydrogenase E3 homodimers at maximal occupancy. Stable E3 integration is mediated by an accessory E3-binding protein (E3BP) located on each of the 12 E2 icosahedral faces. Here, we present evidence for a novel subunit organization in which E3 and E3BP form subcomplexes with a 1:2 stoichiometry implying the existence of a network of E3 "cross-bridges" linking pairs of E3BPs across the surface of the E2 core assembly. We have also determined a low resolution structure for a truncated E3BP/E3 subcomplex using small angle x-ray scattering showing one of the E3BP lipoyl domains docked into the E3 active site. This new level of architectural complexity in mammalian PDC contrasts with the recently published crystal structure of human E3 complexed with its cognate subunit binding domain and provides important new insights into subunit organization, its catalytic mechanism and regulation by the intrinsic PDC kinase.
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Affiliation(s)
- Michaela Smolle
- Division of Biochemistry & Molecular Biology, Institute of Biomedical & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
- Division of Infection & Immunity, Institute of Biomedical & Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Alison Elizabeth Prior
- Division of Biochemistry & Molecular Biology, Institute of Biomedical & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Audrey Elaine Brown
- Division of Biochemistry & Molecular Biology, Institute of Biomedical & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Alan Cooper
- Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
| | - Olwyn Byron
- Division of Infection & Immunity, Institute of Biomedical & Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - John Gordon Lindsay
- Division of Biochemistry & Molecular Biology, Institute of Biomedical & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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